HikariCP/CHANGES

HikariCP Changes

Changes between 1.2.9 and 1.3.0

 *) Pool is now backed by a custom lock-less ConcurrentBag that
    provides superior performance to LinkedBlockingQueue and
    LinkedTransferQueue for usage patterns of connection pools.

 *) Fixed bugs reported against the 1.2.9 release.

 *) Added more detailed logging for broken connections and failures
    during new connection creation.

Changes between 1.2.8 and 1.2.9

 *) Added a fail-fast option for pool initialization.  If enabled, a
    RuntimeException will be thrown if there are errors during pool
    initialization.

 *) Made the registration of the HikariCP MBeans optional.  They now
    default to not being registered.  Registering them causes a minor
    performance hit due to additional pool data collection in
    HikariDataSource.getConnection().

 *) Added the SQLException message to the log entry when an exception
    occurs during physical connection acquisition.

 *) Implemented an orderly shutdown of the pool via the shutdown() method
    on HikariDataSource.

 *) Listened to "Adele - Live At The Royal Albert Hall" on endless loop.

Changes between 1.2.7 and 1.2.8

 *) Fixed a critical bug introduced in 1.2.7 occurring when the number of
    concurrently open statements exceeds sixteen.

Changes between 1.2.6 and 1.2.7

 *) Finally achieved performance parity between the generated delegates
    and the former method of instrumenting driver classes directly.

 *) Improved generated delegate code. Removed unnecessary casts, moved
    to a static proxy factory rather than a singleton (performance win).

 *) Improved performance of FastStatementList (primary source of speed-up
    to reach parity with former instrumentation code).

 *) Removed aliveness check on connection creation.

 *) Track connection isolation level and only reset if the state has
    become "dirty".  Avoids unnecessary round trip to the DB during the
    aliveness check.

 *) Added interface IConnectionCustomizer and related HikariConfig
    property 'connectionCustomizerClassName' to allow users to specify
    a connection customization implementation.

Changes between 1.2.5 and 1.2.6

 *) Fixed regression that caused IndexOutOfBounds when multiple unclosed
    Statements existed at the time of Connection.close().

 *) Fixed incorrect pom.xml dependency on Hibernate.
 
Changes between 1.2.4 and 1.2.5

 *) Instrumentation mode (agent) removed due to narrowing gap between
    delegation mode and instrumentation (and to simplify the code base).

 *) Added setDataSource() to HikariConfig to allow a DataSource instance
    to be explicitly wrapped by the pool.  Only available when creating
    HikariConfig programmatically or constructing HikariConfig from a
    java.util.Properties instance.

 *) Fixed Hibernate threading issue (certain usage patterns) introduced
    in 1.2.2.

 *) Fixed issue observed with PostgreSQL whereby the query that tests the
    connection for "aliveness" also starts a transaction (when auto-commit
    is false), thereby causing a later failure when we tried to set the
    transaction isolation level.

 *) Fixed issue where idleTimeout could not be set to 0, thereby disabling
    it. Incorrect value validation caused 0 to be rejected as a valid value. 

Changes between 1.2.3 and 1.2.4

 *) Fix another Hibernate-related issue whereby an NPE is encountered when
    a thread that was not the thread that obtained a Connection tries to
    interact with that Connection.

Changes between 1.2.2 and 1.2.3

 *) Fix internal (but suppressed) exception during rollback of connections
    returned to the pool with auto-commit turned off.

 *) Fix a reflection issue that causes Hibernate failures due to the
    CallableStatement interface being incorrectly injected into statement
    proxies that are PreparedStatement or Statement instances.

Changes between 1.2.1 and 1.2.2

 *) Perform a rollback() on connections returned to the pool with
    auto commit disabled.

 *) Add a constructor for HikariConfig that accepts a Properties
    object.

 *) Speed improvements for delegate mode.

 *) Fix a bug where connection timeouts could not be disabled.

 *) Permit setting the DataSource logWriter either on the HikariDataSource
    or via addDataSourceProperty() on the HikariConfig.

 *) Add transactionIsolation property to allow setting the default
    transaction isolation level for connections.

Changes between 1.1.9 and 1.2.1

 *) Clear SQL warnings before returning a connection to the user.

 *) Added asynchronous connection backfill strategy that triggers
    when the pool becomes empty as a result of dispatching a
    connection.

 *) Changed default acquireIncrement to 1, set minimum timeout of
    100ms for acquiring a connection.

Changes between 1.1.8 and 1.1.9

 *) Added connectionInitSql property to allow setting connection
    properties when a new connection is created.

 *) Added setDataSourceProperties() setter to HikariConfig to
    allow easier configuration though Spring.